python-event-buffer-use-deque-not-list

Using a Python list with pop(0) for event queues is O(n) per removal and causes latency under high event volume. Replace with collections.deque(maxlen=N) which provides O(1) pops from both ends and automatic oldest-entry eviction at capacity. This pattern applies to all bridge connector event buffers (mc_connector.py, and any future bridge connector).